reference added

Author: Arjun

README.md

@@ -180,7 +180,7 @@ Argument list should be different while doing method overloading. Argument list
 * What is a LocalBroadcastManager? [Link](https://developer.android.com/reference/android/support/v4/content/LocalBroadcastManager.html)
 * What is a JobScheduler? [Link](http://www.vogella.com/tutorials/AndroidTaskScheduling/article.html)
 * What is DDMS and what can you do with it?
-* What is the support library? Why was it introduced?
+* What is the support library? Why was it introduced?[Link](http://martiancraft.com/blog/2015/06/android-support-library/)
 * What is a ContentProvider and what is it typically used for?
 * What is Android Data Binding? [Link](https://developer.android.com/topic/libraries/data-binding/index.html)
 * What are Android Architecture Components? [Link](https://developer.android.com/topic/libraries/architecture/index.html)